BROADBAND, UNDERWATER ACOUSTIC DEVICES FOR AMBIENT NOISE MEASUREMENTS

摘要

1 INTRODUCTION The market of preamplified hydrophones is currently dominated by either professional measurement devices (e.g., [1,2,3]) or commercial devices [4], which are generally not easy to use, in particular to connect to a commercial acquisition system. In addition, they suffer: ? signal decay on the cable, which can be significant particularly at high frequency, and ? external electromagnetic interference (e.g., cross-talk, etc.). A recent solution has been proposed by SMID Technology [5] which consists of digital hydrophones, having the digitalization module close to the hydrophone. They overcome the main drawbacks of the analog hydrophones related to signal loss along cable and influence by electromagnetic interferences, but require dedicated receiving boxes, dedicated acquisition software tools, possibly proprietary protocols; hence they may be not so user friendly.